A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. comprising part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
In lithography of IC and other devices, there is typically a demand for increasing the throughput of a lithographic apparatus as throughput typically relates to the profitability of the lithographic apparatus. Thus, there is a desire to quickly handle articles, such as substrates or patterning devices, that are involved in the lithographic process. However, due to the cleanliness and other limiting factors, only certain handling mechanisms can provide the handling of these articles into and within the lithographic apparatus. One of the mechanisms is a vacuum clamp which is used, for example, in the substrate handler to handle the substrates, for instance, when transported into and out of the lithographic apparatus. Such a vacuum clamp may also be used when the substrate is held on the substrate table for exposure. To provide the clamping action of the clamp, the clamp is coupled to a gas pressurizing device, comprising a pressure circuit that is connected to the article clamp.